> most SaaS products contain many features that many customers don't need or use. A lot of the complexity in SaaS product engineering is managing that - which evaporates overnight when you have only one customer (your organisation).

This is the key point. Sure, you don't have the chops to be able to replicate the SaaS product locally with Claude/Gemini, but you don't have to, because you're no trying to make a product that can handle N+1 workflows.